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Chapter 1
Introduction to Chemistry
1.1 The Scope of Chemistry 1.2 Chemistry and You
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In 1928, Alexander Fleming, a Scottish
scientist, noticed that the bacteria he was studying did not grow in the
presence of a yellow-green mold.
CHEMISTRY & YOU
CHEMISTRY & YOU
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An Experimental Approach to Science
How did Lavoisier help to
transform chemistry?
An Experimental
An Experimental
Approach to Science
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The word
chemistry
comes from the word
alchemy
.
• Alchemists were concerned with searching for a way to change other metals, such as
lead, into gold.
• Alchemists developed the tools and techniques for working with chemicals. • They designed equipment
that is still in use today,
including beakers, flasks, tongs, funnels, and the mortar and pestle.
An Experimental
An Experimental
Approach to Science
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1.3 Thinking Like a Scientist > An Experimental An Experimental
Approach to Science
Approach to Science
In France, Antoine-Laurent Lavoisier did work in the late 1700s that would revolutionize the
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An Experimental
An Experimental
Approach to Science
Approach to Science
Lavoisier helped to transform
chemistry from a science of
observation to the science of
measurement that it is today.
In France, Antoine-Laurent Lavoisier did work in the late 1700s that would revolutionize the
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1.3 Thinking Like a Scientist > An Experimental An Experimental
Approach to Science
Approach to Science
• Lavoisier designed a balance that could
measure mass to the nearest 0.0005 gram. • He also settled a long-standing debate about
how materials burn.
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8 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Who is credited with transforming
chemistry from a science of observation to a science of measurement?
A. Fleming
B. Lavoisier
C. de Mestral
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Who is credited with transforming
chemistry from a science of observation to a science of measurement?
A. Fleming
B. Lavoisier
C. de Mestral
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1.3 Thinking Like a Scientist >
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The Scientific Method
The Scientific Method
The Scientific Method
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1.3 Thinking Like a Scientist > The Scientific MethodThe Scientific Method
The scientific method is a logical,
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The Scientific Method
The Scientific Method
Steps in the scientific method
include making observations,
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1.3 Thinking Like a Scientist > The Scientific MethodThe Scientific Method
Making Observations
When you use your senses
to obtain information, you
make an observation.
• This scientist is making observations with a
microscope.
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The Scientific Method
The Scientific Method
Making Observations
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1.3 Thinking Like a Scientist > The Scientific MethodThe Scientific Method
Testing Hypotheses
• A hypothesis is a proposed explanation for an observation.
If you guess that the batteries in a
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The Scientific Method
The Scientific Method
Replacing the batteries is an experiment,
a procedure that is used to test a
hypothesis.
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1.3 Thinking Like a Scientist > The Scientific MethodThe Scientific Method
Replacing the batteries is an experiment,
a procedure that is used to test a
hypothesis.
• The variable that you change during an experiment is the independent variable, also called the manipulated variable.
• The variable that is observed during the experiment is the dependent variable, also called the responding variable.
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The Scientific Method
The Scientific Method
For the results of an experiment to be
accepted, the experiment must produce
the same result no matter how many
times it is repeated, or by whom.
• This is why scientists are expected to publish a description of their procedures along with their results.
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1.3 Thinking Like a Scientist > The Scientific MethodThe Scientific Method
Sometimes the experiment a scientist
must perform to test a hypothesis is
difficult or impossible.
• For example, atoms and molecules, which are some of the smallest units of matter, cannot be easily seen.
• A model is a representation of an object or event.
• Chemists may use models to study chemical
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The Scientific Method
The Scientific Method
Developing Theories
Once a hypothesis meets the test of
repeated experimentation, it may be
raised to a higher level of ideas. It may
become a theory.
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1.3 Thinking Like a Scientist > The Scientific MethodThe Scientific Method
Developing Theories
• When scientists say that a theory can
never be proved, they are not saying that a theory is unreliable.
• They are simply leaving open the
possibility that a theory may need to be changed at some point in the future to
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The figure below shows how scientific
experiments can lead to laws as well as
theories.
The Scientific Method
The Scientific Method
Scientific Laws
Experiments
An experiment can lead to observations that support or
disprove a hypothesis.
Theory
A theory is tested by more experiments and modified if necessary.
Hypothesis
A hypothesis may be revised based on experimental data.
Observations
Scientific Law
A scientific law
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1.3 Thinking Like a Scientist > The Scientific MethodThe Scientific Method
A scientific law is a concise statement
that summarizes the results of many
observations and experiments.
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The Scientific Method
The Scientific Method
A scientific law is a concise statement
that summarizes the results of many
observations and experiments.
• A law doesn’t try to explain the relationship it describes.
• That explanation requires a theory.
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1.3 Thinking Like a Scientist > CHEMISTRYCHEMISTRY && YOUYOU
What was Alexander Fleming’s
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Other scientists had made the same observation, but
Fleming was the first to
recognize its importance. He assumed that the mold had released a chemical that
prevented the growth of the bacteria.
CHEMISTRY & YOU
CHEMISTRY & YOU
What was Alexander Fleming’s
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What is a hypothesis?
A. information obtained from an experiment
B. a proposed explanation for observations
C. a concise statement that summarizes the results of many experiments
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What is a hypothesis?
A. information obtained from an experiment
B. a proposed explanation for observations
C. a concise statement that summarizes the results of many experiments
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Collaboration and Communication
What role do collaboration and
communication play in science?
Collaboration and
Collaboration and
Communication
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• No matter how talented the players on a team may be, one player cannot ensure victory for the team.
• Individuals must collaborate, or work together, for the good of the team.
Collaboration and
Collaboration and
Communication
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When scientists collaborate and
communicate with one another,
they increase the likelihood of a
successful outcome.
Collaboration and
Collaboration and
Communication
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Collaboration
Scientists choose to collaborate for
different reasons.
• Some research problems are so complex that no one person could have all the
knowledge, skills, and resources to solve the problem.
Collaboration and
Collaboration and
Communication
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Collaboration isn’t always a smooth
process.
• Working in pairs or in a group can be challenging, but it can also be rewarding.
Collaboration and
Collaboration and
Communication
Communication
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Communication
The way scientists communicate with
each other and with the public has
changed over the centuries.
• Scientists working as a team can communicate face to face.
• They also can exchange ideas by e-mail, by phone, and at local and international
conferences.
• They publish their results in scientific journals. Collaboration and
Collaboration and
Communication
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Scientific journals are the most reliable source of information about new discoveries.
• Articles are published only after being reviewed by experts in the author’s field. • Reviewers may find errors in experimental
design or challenge the author’s conclusions. • This review process is good for science
because work that is not well founded is
Communication
Collaboration and
Collaboration and
Communication
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36 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Why are articles in scientific journals the most reliable source of information about new scientific discoveries?
A. The articles are reviewed by experts in the author’s field.
B. Any article that is submitted is published.
C. Everyone has access to the information.
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Why are articles in scientific journals the most reliable source of information about new scientific discoveries?
A. The articles are reviewed by experts in the author’s field.
B. Any article that is submitted is published.
C. Everyone has access to the information.
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Key Concepts
Key Concepts
Lavoisier helped to transform chemistry from a science of observation to the
science of measurement that it is today.
Steps in the scientific method include making observations, testing
hypotheses, and developing theories.
When scientists collaborate and
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1.3 Thinking Like a Scientist > Glossary TermsGlossary Terms
• scientific method: a logical, systematic approach to the solution of a scientific problem; steps in the scientific
method include making observations, testing hypotheses, and developing theories
• observation: information obtained through the senses; observation in science often involves a measurement
• hypothesis: a proposed explanation for an observation
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Glossary Terms
Glossary Terms
• independent variable: the variable that is changed during an experiment; also called manipulated variable
• dependent variable: the variable that is observed during an experiment; also called responding variable
• model: a representation of an event or object
• theory: a well-tested explanation for a broad set of observations
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Chemists use the scientific method to
solve problems and develop theories
about the natural world.
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